ICC Profile Color FeedBack Test

When comparing color values in an ICC profile to the color values in the measured file from which that ICC profile was generated why are they a bit different? The average delta E errors can be around 0.5 with highest at around 1. Is this due to limitation in size of the CLUT or CPU processing power to fit the points perfectly or some other mathematical reasons that require maybe for overall accuracy or smoothness or etc.?

ICC profile color feedback

Hi,

Yes, we too got similar differences. After few trials, we found out that when we measure data once, there is always a possibility of errors in the measurement due to various reasons like dirt in test form, movement of spectrophotometer is fast, uneven inking etc. Hence we do smoothing option many times which results in bigger deviations between ICC profile and measurement data. The test target also made the difference.

We used new IT8 targets which has more number of patchs and also we started measuring 10 sheets of printing and taking the average of the ten to make the icc profile. We didn't smoothen the profile.

We used Heidelberg color tool box and now the average value is less than Delta E 0.3. Hope it helps.

PS: we make our own custom profiles for our speciality papers we print in our Heidelberg press.

In my opinion it depends on the quality of the profiling engine, the amount of smoothness and gray neutralization it applies + the profiling engine trying to filter out noise and measurement inconsistencies (as also stated here: [URL="http://argyllcms.com/doc/profcheck.html"]http://argyllcms.com/doc/profcheck.html[/URL])